Most of fungi having pathogenicity for human have two-phase property that is to say, they can take both a yeast form and a mycelium form depending on environmental conditions. Some of the fungi do not have the two-phase property. In the yeast form, they exist as a single cell having a egg-like sphere, and will divide and grow through a process of budding. The mycelium form show a branched filamentous structure that is called mycelium, which consists of tandem cells with a cylindrical-shape or of multinuclear and elongated cells.
Such fungi include Candida, Cryptococcus, Aspergillus, etc. Candida are a normal inhabitant in oropharynges and digestive organs of healthy individuals. Cryptococcus are not only very often contained in soul and feces of a pigeon and a mouse, but also present in a humid place such as in a room. They will be carried by wind and contact humans. Aspergillus have been found since early times in soul and feces of birds, and recently they are very often found also in an air conduct and filter in a hospital. Although these fungi have a low infectious capacity for healthy individuals, they will release tissue-destructing substances such as exotoxin, endotoxin and protease. Most of the fungi will grow in patients receiving administration of anticancer agents, immunosuppressive agents, steroid agents, and broad-spectrum antibiotics, and show characteristics of opportunistic infection. Cell-mediated immunity in healthy individuals would sufficiently function against these fungi and serve as phylaxis. But, as the cell-mediated immunity in the above patients has been compromised, the infection would be permitted. Especially, in the cases of patients suffering from malignant diseases, patients with a transplanted organ, patients treated in an intensive care unit and the like, the above fungi would cause deep-seated mycosis such as deep candidiasis, or candidaemia, and would often have a severe outcome.
Amphotericin B belonging to polyenes is known as a therapeutic agent against these mycotic diseases. Antifungal agents such as flucytosine, ketoconazole and miconazole of imidazoles are known as well.    [Patent Document 1] Japanese Patent No. 3472821, Novel peptide, and Composition comprising the peptide    [Patent Document 2] Japanese Patent No. 3546231, Novel peptide, and Composition comprising the peptide    [Non-Patent Document 1] Oral Diseases (2004) 10, 221-228, Fungicidal effect of three new synthetic cationic peptides against Candida albicans 